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Questions and Answers
What is the primary method of communication between neurons called?
What is the primary method of communication between neurons called?
Glial cells only function as support cells and do not play any role in the communication between neurons.
Glial cells only function as support cells and do not play any role in the communication between neurons.
False
What is the role of the sodium-potassium pump in neurons?
What is the role of the sodium-potassium pump in neurons?
To maintain the resting membrane potential by actively transporting sodium out of and potassium into the cell.
The __________ is the structure at the end of an axon that contains neurotransmitter sacs.
The __________ is the structure at the end of an axon that contains neurotransmitter sacs.
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Match the parts of a neuron with their functions:
Match the parts of a neuron with their functions:
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What triggers the release of neurotransmitters into the synapse?
What triggers the release of neurotransmitters into the synapse?
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Neurotransmitters are released from the dendrites of a neuron.
Neurotransmitters are released from the dendrites of a neuron.
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What is the action potential?
What is the action potential?
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What is the resting potential of a neuron?
What is the resting potential of a neuron?
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The sodium-potassium pump moves two sodium ions into the cell for every three potassium ions it pumps out.
The sodium-potassium pump moves two sodium ions into the cell for every three potassium ions it pumps out.
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What is the threshold potential required for an action potential to propagate?
What is the threshold potential required for an action potential to propagate?
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The process by which excess neurotransmitters are returned to the pre-synaptic neuron is called ______.
The process by which excess neurotransmitters are returned to the pre-synaptic neuron is called ______.
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Which of the following describes the All or Nothing Principle?
Which of the following describes the All or Nothing Principle?
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During repolarization, sodium channels open while potassium channels close.
During repolarization, sodium channels open while potassium channels close.
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Match the following neurotransmitter functions with their descriptions:
Match the following neurotransmitter functions with their descriptions:
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What occurs at the Node of Ranvier during action potential propagation?
What occurs at the Node of Ranvier during action potential propagation?
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Which neurotransmitter is considered the major excitatory neurotransmitter in the brain?
Which neurotransmitter is considered the major excitatory neurotransmitter in the brain?
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GABA is primarily an excitatory neurotransmitter in the brain.
GABA is primarily an excitatory neurotransmitter in the brain.
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What role does dopamine play in human behavior?
What role does dopamine play in human behavior?
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_____ is a neurotransmitter that controls muscle movement and is involved in learning and memory.
_____ is a neurotransmitter that controls muscle movement and is involved in learning and memory.
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What can excessive levels of glutamate lead to?
What can excessive levels of glutamate lead to?
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Match the neurotransmitter with its primary effect:
Match the neurotransmitter with its primary effect:
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Norepinephrine is responsible for activating the sympathetic response to stress.
Norepinephrine is responsible for activating the sympathetic response to stress.
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Individuals with depression tend to have lower levels of _____.
Individuals with depression tend to have lower levels of _____.
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Study Notes
The Biological Approach
- The biological approach emphasizes the role of the brain, neurotransmitters, hormones, and genes in explaining behavior and mental processes.
Organization of the Nervous System
- The nervous system is organized into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
- The CNS consists of the brain and spinal cord, whereas the PNS comprises all the nerves outside the CNS.
- The PNS is then subdivided into the somatic nervous system and the autonomic nervous system.
- The somatic nervous system controls voluntary movements.
- The autonomic nervous system controls involuntary functions, like heart rate and digestion. It has two main branches: the sympathetic nervous system and the parasympathetic nervous system.
- The sympathetic nervous system is associated with 'fight or flight' responses.
- The parasympathetic nervous system is associated with 'rest and digest' responses.
- The PNS is then subdivided into the somatic nervous system and the autonomic nervous system.
Central Nervous System
- The central nervous system (CNS) comprises the brain and spinal cord.
- It is responsible for receiving, processing, and sending information throughout the body.
Peripheral Nervous System
- The peripheral nervous system (PNS) consists of all the nerves outside the brain and spinal cord.
- It is responsible for communicating information to and from the CNS.
- The somatic nervous system controls voluntary activities.
- The autonomic nervous system regulates involuntary actions.
Autonomic Nervous System
- All of the nerves in the peripheral nervous system that serve involuntary systems of the body.
- The autonomic nervous system is responsible for involuntary bodily processes.
- This system is divided into two sub-divisions: Sympathetic and Parasympathetic.
Sympathetic Nervous System
- Activates the body during emergency conditions.
- Responsible for 'fight or flight' responses.
- It diverts blood from the digestive systems, thus directing it towards muscles and lungs.
Parasympathetic Nervous System
- Calms the body down after a 'fight or flight' response.
- Responsible for 'rest and digest' responses.
- It diverts blood to digestive systems, slowing the heart rate.
Origins of Neuron Doctrine
- Humoral theory: The theory that the human body is comprised of 4 types of fluids (blood, phlegm, yellow bile, black bile).
- Camillo Golgi: Used a staining technique to illustrate neurons. Still believed the nervous system was continuous.
Neuron Doctrine
- Santiago Ramón y Cajal: Father of modern neuroscience.
- He discovered that the nervous system is composed of individual neurons separated by synapses.
Electrical and Chemical
- The nerve impulse, or action potential, is both electrical and chemical.
- Electrical transmission occurs within a neuron, while chemical transmission occurs between neurons at synapses. This process involves neurotransmitters.
- The action potential is the signal of information within a neuron, and neurotransmitters are the chemicals that carry the signal between neurons.
Glial Cells
- Glial cells support, protect, and insulate neurons.
- The blood-brain barrier, a critical function, is partly made up of glial cells
- Critical for neuron functioning.
Structure of a Neuron
- Neurons consist of cell bodies, axons, dendrites, myelin sheath, synapses, terminal buttons, and glial cells.
- Key structures of the neuron are the cell body (soma), dendrites, axon, myelin sheath, axon terminals, and the node of Ranvier
The Neuron
- The basic unit of the nervous system.
- Receives and transmits information.
- Information travels as an electrical signal within a neuron and as a chemical signal between neurons.
The Soma
- The cell body of the neuron.
- Contains the nucleus and other organelles.
- Receives signals from other neurons through dendrites.
- Generates the action potential.
The Axon
- A long projection extending from the soma.
- Transmits electrical signals (action potentials) away from the soma.
- Myelin sheath around the axon increases the speed of signal transmission.
- The axon terminal contains neurotransmitters.
The Terminal Button
- Knob at the end of an axon.
- Contains synaptic vesicles filled with neurotransmitters,
- Release of neurotransmitters into the synapse.
The Action Potential (Electrical Signal)
- A rapid change in the electrical potential of a neuron.
- Involves the movement of sodium and potassium ions across the neuronal membrane.
- Three phases: Resting potential, Depolarisation, Repolarization
- Resting Potential: neuron is at its normal polarized state (-70mV)
- Depolarisation: a shift towards a positive membrane potential (+40mV) caused by inflow of sodium ions
- Repolarisation: return from positive to negative membrane potential (-70mV) caused by outward flow of potassium ions
The Node of Ranvier
- Gaps in the myelin sheath.
- Enable the rapid transmission of the action potential through saltatory conduction.
- Action potential "jumps" across the nodes.
Repolarization
- The process that restores the neuron to its resting potential (-70mV).
- Involves K+ ions flowing out of the neuron.
Neurotransmission
- The communication between neurons that involves neurotransmitters.
- Once the action potential reaches the terminal button, the electrical signal ends. The chemical signal begins
- Chemicals that transmit information between neurons.
- Synaptic vesicles release NTs into the synaptic cleft.
Neurotransmitters (NTs):
- Chemicals that carry signals across synapses.
- Different NTs have different effects on the receiving neuron.
- Neurotransmitters bind to receptor sites to influence a post-synaptic neuron
What Happens After Neurotransmitters are Released?
- Reuptake: Excess neurotransmitters are reabsorbed by the presynaptic neuron.
- Enzymatic degradation: Specialized enzymes break down the neurotransmitters.
Neurotransmitter Examples
- Glutamate, GABA, Acetylcholine, Dopamine, Serotonin, Epinephrine, Norepinephrine.
Glutamate and GABA
- Glutamate: principal excitatory neurotransmitter involved in learning & memory. Too much can cause seizures.
- GABA: major inhibitory neurotransmitter; slows down brain activity, crucial for regulating neural activity
Acetylcholine
- Controls muscle movement, learning & memory.
- Found at neuromuscular junctions.
Dopamine
- Released in response to rewarding behaviors; involved in voluntary motor control and addictive behavior
Serotonin
- Involved in sleep & dreaming; regulates emotional states; associated with depression.
Epinephrine and Norepinephrine
- Arousal and alertness.
- Associated with stress responses and rapid action; increases heart and breathing rate.
The Brain
- The control centre for the body.
- Consists of different sections with different functions
The Hindbrain
- Oldest part of the brain
- Includes the medulla, pons, and cerebellum.
- Regulates basic bodily functions (breathing, heart rate, blood pressure).
- Coordinates movement and balance.
The Midbrain
- The middle part of the brain
- Includes the reticular formation
- Important in sleep-wake cycles & arousal.
The Forebrain
- The biggest part of the brain.
- Includes the thalamus, hypothalamus, limbic system & cerebral cortex.
- Controls complex cognitive and emotional functions.
The Limbic System
- Important in regulating emotions, motivation, and memory.
- Includes structures like the hippocampus, amygdala, and hypothalamus.
Hippocampus
- A limbic structure essential for learning and memory.
- Important for converting short-term memories into long-term memories
Amygdala
- An almond-shaped structure involved in processing emotions, particularly fear
Cingulate Gyrus
- Involved in attention, cognitive control, and emotion.
Basal Ganglia
- Involved in motor control.
- Associated with conditions like Parkinson's disease.
The Changing Brain
- Neuroplasticity: The brain's ability to change and adapt throughout life by forming new connections based on experience and learning.
- Necessary for learning and memory.
- The brain does not waste any area or neuron, so it is very active and adaptive.
The Cerebral Cortex
- Responsible for higher-level functions.
- Divided into four lobes: Frontal, Parietal, Occipital, Temporal.
- The outer layer of the cerebrum.
The Cerebral Hemispheres
- Two halves of the brain.
- Some functions are predominantly located on one hemisphere.
Corpus Callosum and Insula
- Corpus Callosum: Nerve fibers connecting the two hemispheres.
- Insula: Involved in bodily sensations, emotions, and empathy.
Split Brain
- A surgical procedure that severs the corpus callosum.
- Demonstrates the lateralization of brain function.
The Motor Cortex
- Responsible for voluntary movements of skeletal muscles.
The Parietal Lobe
- Involved in processing sensory information.
- Perception of spatial relationships.
Hemispheric Neglect
- A condition where individuals fail to attend to one side of space.
The Somatosensory Cortex
- Sensory information from the body (pressure, temperature, pain)
- Processing of sensory information
The Occipital Lobe
- Visual cortex; responsible for processing visual information.
- Perception and interpretation of visual stimuli.
The Temporal Lobe
- Primarily auditory cortex, responsible for processing auditory information.
- Also involved in memory and language.
Aphasia
- Difficulty in understanding or producing language.
- Caused by damage to Broca's or Wernicke's areas.
Frontal Lobe
- Higher cognitive functions (planning, decision-making).
- Prefrontal cortex.
- Motor control
Phineas Gage
- A famous case study illustrating the importance of the frontal lobe in personality and behavior.
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